Potential-regulator for alternating-current circuits.



No. 742,926. PATENTED NOV. 3, 1903.

H. R. STUART.

POTENTIAL REGULATOR FOR ALTBRNATING GURRENT CIRCUITS. APPLICATION FILED MAR. 12. 1903.

10 MODEL. 2 SHEETS-SHEET 1. Fig.1

Z5 66 2f 2/ 26' 35 L 2a 2.9 v 0 1 J WITNESSES: V INYENTOH No. 742,926. PATENTED NOV. 3, 1903. H. R. STUART.

POTENTIAL REGULATOR FOR ALTERNATING CURRENT CIRCUITS.

APPLICATION FILED MAR. 12. 1903 N0 MODEL. 2 SHEETS-SHEET 2.

W-ITNESSESI INVENTUH are. 742,926.

UNITED STATES Patented November 3, 1903.

PATENT ()FFICE.

I-IARVE R. STUART, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A COR- PORATION OF PENNSYLVANIA.

POTENTIAL-REGULATOR FOR ALTERNATlNG-CURRENT CIRCUITS.

SPECIFICATION forming part of Letters Patent No. 742,926, dated November 3, 1903.

Application filed March 12, 1903. Serial No. 147,539. (No model.)

To ctZZ whom it may concern.-

Be it known that I, HARVE R. STUART, a citizen of the United States, residing in Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Potential-Regulators for Alternating-Current Circuits, of which the following is a specification.

My invention relates to apparatus for regulating and controlling the voltage of alternating-current circuits; and it has for its object to provide apparatus of this character which shall be comparatively simple and inexpensive and which maybe easily manipulatedand not liable to disarrangement or destruction in service.

My invention is illustrated in the accompanying drawings, in which Figure 1 is a diagram illustrating the arrangement and circuit connections of transformer-coils adapted to form part of my regulating apparatus. Fig. 2 is a diagram of one form of my regulator and a circuit the voltage of which is to be regulated. Fig. 3 is a sectional view of the controlling-switch shown in Fig. 2. Figs. 4, 5, 6, and 7 are diagrams of different modifications of a regulator embodying my invention. Fig. 8 is a diagram corresponding to Fig. 2, but embodying a switching device of different construction.

Referring first to Figs. 1, 2, and 3, my invention is shown as comprising a transformer 1, having a primary winding 2 of invariable length and two secondary windings 3 and 4, having spaced leads 5, connected to a regulating-switch 6, whereby their active lengths may be varied in a manner to be hereinafter described. As here shown, the primary winding 2 of the transformer 1 is connected in series with an alternating-current generator 7, and the active length of the one or the other of the secondary windings 3 and 4 is connected in shunt relation to the primary winding to supply translating devices 8 through the regulating-switch 6. The regulating-switch is here shown as comprising an annular-lydisposed set of stationary contact-terminals 9, two contact-rings 10 and 11, a movable arm 12, which has a contact-piece 12, that makes engagement with the set of contactterminals 9 and the inner ring 10, and an arm 13, which has a similar contact-piece 13, that makes engagement with the contact-terminals 9 and the outer ring 11. The arm 13 is rigidly mounted upon a shaft 14:, the outer end of which is provided with an operating arm or handle 15, having a latch device 16 that engages with notches 17 in a ring 18 in order to insure proper registration of the movable contact-pieces with the stationary contact-terminals.

Surrounding the shaft 14 is a sleeve 19, from one end of which projects the shorter arm 12 and on the other end of which is rigidly mounted a bevel gear-wheel 20. On the shaft 14 is rigidly mounted a second bevel gear-wheel 21, and a suitable idler-pinion 22 is supported upon a suitable bracket 23 in position to engage with both gear-wheels, so that as the operating-handle 15 is moved in the one direction or the other the two switcharms 12 and 13 will be moved in opposite directions at the same speed.

The outer contact-ring 11 is permanently connected to one side of the work-circuit, and the inner contact-ring ,10 is connected directly to one terminal of the generator 7. As the spaced leads 5 of the two transformer secondaries 3 and 4. are alternately connected to consecutive contact-terminals of the set 9, the active lengths of the two secondaries will be alternately varied as the switch is operated, and the work-circuit electromotive force will be correspondingly increased or decreased, according to the direction of movement of the respective arms 12 and 13.

In order to avoid short-circuiting the central portion of the secondary winding 3 when the switch-arms pass each other at the middle of the set of contact-terminals 9, I provide two contact-terminals 9 and 9 to which are con nected the terminals of a suitable preventive resistance 24. This may be either an inductive or a non-inductive resistance, as may be found desirable in practice.

In order that the transformer constituting a part of my regulating apparatus may have satisfactory regulation between the primary and each secondary winding and at the same time have as much magnetic leakage between the two secondary windings as possible, I arrange the coils as indicated in Fig. 1. In operating this regulator it is necessary to connect for an instant one part of one of the secondarywindings havingagiven voltage in parallel with a part of the other secondary winding having a lower voltage, so that a local current is set up through and between the two secondaries. This local current is greatly reduced and kept within practical working limits by the magnetic leakage between the two secondaries.

As indicated in Fig. 2, when the regulator is working near the center of transformer-secondary circuits the length of winding is rela tively so small that the local currents set up as above mentioned are relatively large, Whereas when working at some considerable distance from the center there are manyturns in series, and consequently a relatively high self-induction which tends to reduce the local currents.

In order to approximately equalize the conditions, I so locate and connect the secondary coils (there being threecoils 25, 26, and 27 and 25, 26, and 27 for the respective secondary windings, as indicated in Fig. 1) that the coils containing the windings which are at and near the centers of the circuits of the transformer are located at the ends of the transformer structure, while the coils containing the portions of the windings which are farthest from the center electrically are located in the middle of the transformer structure. WVith this arrangement of coils the primary Winding comprised in coils 28, 29, 30, and 31 is symmetrically disposed with reference to the secondary windings, and though only one of the latter is in use at one time the symmetrical relation is not disturbed, and good results are secured.

With the switch-arms 12 and 13 in the positions shown in Fig. 2 the entire transformer secondary 3 is in circuit and the secondary 4 is inactive. By movingthe arms one step the secondary 3, which was first in circuit, is rendered inactive, and .the other secondary 4 is in circuit. A still further step removes the secondary 4 from the circuit and transfers the circuit connections of the secondary 3 to the second pair of spaced leads 5. This transfer of the circuit connections from the one secondary to the other step by step may be continued until the stationary contact-terminals corresponding to the inner pair of leads 5 are reached. Further movement of the operating-handle 15 in the same direction will first connect the preventive resistance 24 in circuit and then each secondary will be step by step alternately connected into circuit; but, since the arms 12 and 13 have crossed each other in passing the preventive resistance 24 the circuits will be reversed, and if the previous action was a boosting or reinforcing one the reverse effect will now be produced and the effect will beincreased step by step until the entire secondary is in circuit.

In Fig. 4 the arrangement of transformerwindings and switching device is or may be the same as indicated in Fig. 2 except that the preventive resistance is connected across two contacts 9 and 9,which are transversely disposed with reference to the path of movement of the switch arms instead of in line therewith.

In Fig. 5 the combination and arrangement of parts are substantially the same as in Fig. 4, except that two preventive resistances 24 and 24 are shown, which are connected, respectively, between side-by-side contact-terminals 9 and 9 and corresponding points in the secondary winding 3.

In Fig. 6 I have shown two transformer secondaries 3 and 4, one of which is intended to be in service only momentarily, the running contacts 32 being connected to the secondary 3 and the intermediary contacts 33, which merely designate transition-points, being connected to the other secondary winding 4. The two windings are therefore permanently connected at their ends by preventive resistances 34, and theyare also connected in circuit through a reversing-switch 35, this switch being essential in this form, since there is only one contact ring or strip 36 and one contact-arm 37, having a brush or shoe 37, to make engagement therewith and simultaneously with one of the contact-terminals 32 33.

In Fig. 7 the arrangement of parts is similar to that shown in Fig. 6, except that only one preventive resistance is shown, which is located between corresponding ends of the transformer secondaries, and the reversingswitch 35 is located in the circuit of the primary winding of the transformer. In this form, as in Fig. (i, the secondary winding 4 is only momentarily in circuit, and the contact-terminals 33 are merely transition-points. The single brush or shoe 37 of the switching device makes only momentary contact with each terminal piece 33 as it passes from one to the other of the adjacent terminal pieces 32, which are connected to the secondary winding 3.

In Fig. 8 I have shown a switching device comprising two sets of stationary contactpieces 38 and 38, which are oppositely disposed in arcs of circles and which are crossconnected by conductors 39 and alternately joined to the spaced leads 5 of the two secondaries 3 and 4. I provide also two ringsegments 40 and 41, which are respectively connected to one side of the work-circuit, the voltage of which is to be regulated, and to one terminal of the generator 7. A single contact-arm 42 is provided at its respective ends with contact shoes or brushes 43 and 44, which bridge the space between the corresponding ring-segments and the adjacent stationary contact-terminals, the two center contact-terminals being cross-connected through a preventive resistance 45. The voltage reinforcing and reducing actions are effected ICC without a reversing-switch by reason of the fact that when the contact-arm 42 passes the center it effects a reversal of the windings.

The designation herein of certain windings as primary and of certain others as sec ondary is not to be construed as limiting the relation of said windings with reference to each other or with reference to the external circuit, except as limitations may be imposed by the conditions of practical operation.

Other forms of switching apparatus might be devised for practicing my invention, and I therefore desire it to be understood that limitations as to form, dimensions, and relative location of parts are to be supplied only as they may be imposed by the prior art.

It is to be also understood that neither the apparatus as a Whole nor any of its parts that are separately claimed is to be restricted by the description to any specific use provided other uses are found therefor.

I claim as my invention- 1. Atransformerhavinga plurality of windings which are severally provided with spaced leads, in combination with a single switching device having stationary contact-terminals to which said leads are connected and one or more movable contact members the movement of which serves to vary the active length of both of said windings.

2. Atransformerhaving coils provided with spaced leads and having such cross connections that the outer or end coils constitute the inner or middle portions of the circuit or circuits.

3. Atransformerhavingaplurality of windings each of which comprises electricallyconnected but physically-separated coils, the electrical connections being such that the outer coils constitute the inner portions of the circuit.

4. A transformer having a primary winding and two secondary windings, the latter being provided with spaced leads and consisting of coils which are so connected that the outer coils constitute the inner portions of the windings, in combination with a switching device connected to the spaced leads and cooperating therewith to vary the active lengths of the windings.

5. A voltage-regulator comprising a transformer having a primary winding and two secondary windings the coils of which are so disposed and connected that the outer ones constitute the inner portions of the circuits, in combination with a switching device comprising one or more movable members, one or more sets of stationary contact-terminals and conductors leading therefrom to difierent portions of said secondary windings.

6. In a voltage-regulator, a transformer having one of its windings provided with spaced leads, a set of contact-terminals to which said leads are connected, two movable contact members and means for moving said members in unison in opposite directions to vary the active length of said winding symmetrically with reference to the other winding.

7. A voltage-regulator for alternating-current circuits, comprising a winding of nonvariable length and two windings having spaced leads and composed of coils so disposed and connected that the outer coils constitute the inner portions of the circuits, in combination with a switching device connected to said spaced leads and adapted for operation to vary the active lengths of said windings in alternation.

In testimony whereof I have hereunto subscribed my name this 5th day of March, 1903.

HARVE R. STUART.

Witnesses:

A. B. REYNDERs, JAMES B. YOUNG. 

